The genus Cataulax was described by Spinola (1837). So far, the species belonging to Cataulax have been known only from the original descriptions except for Stål's (1872) comments on Cataulax eximius Walker, 1868 and Cataulax subvittatus Walker, 1868 but he did not mention the remaining species described by Walker (1868), Cataulax annulicornis and Cataulax punctipes. Lethierry & Severin (1893) listed C. eximius, C. subvittatus, C. annulicornis, C. punctipes and Cataulax decoloratus Walker, 1868 in their catalogue. Besides the species cited in Lethierry & Severin's (1893) catalogue, except C. decoloratus, Kirkaldy (1909) added Cataulax varicornis (Walker, 1867) in his catalogue.

Stål (1860) described the genus Hypata for Hypata eximia, from Rio de Janeiro, Brazil. Stål (1872) pointed out Hypata as a junior synonym of Cataulax.

The genus Architas was described by Distant (1889) for Architas pudens, from Panama. The original description remained so far the only reference to it, except for its inclusion in Kirkaldy's (1909) catalogue.

Distant (1899) considered C. decoloratus Walker, 1868 a junior synonym of Pentatoma varicornis Walker, 1867 which he transferred to Cataulax. Ruckes (manuscript) considered these species congeneric with Ablaptus Stål, 1864. A note concerning these species can be found in Becker & Grazia (1997).

The remaining species described by Walker (1868) for this genus such as C. punctipes, C. annulicornis and C. subvittatus were considered here as incertae sedis. According to the original descriptions the types of the first two species were deposited in the "National Museum at Melbourne", and the type of the third species in the "British Museum (Bates Collection)". The types of C. annulicornis and C. punctipes were not found at the Museum of Victoria (formerly National Museum of Victoria) according to the information of Ms. Catriona McPhee, Assistant Curator, Entomology. The type of C. subvittatus was not found at the National Museum, London, according to Mrs. Janet Margerison-Knight, formerly Curator of the collection. Furthermore, Walker's descriptions of these species do not permit to place them correctly.

Measurements are given in millimeters, and were obtained as in Becker & Grazia (1989). The pygophores, and females genital plates were illustrated in dry condition; phallus, and females ectodermal genital ducts were studied after boiling in KOH 10% and staining in Congo Red. The terminology of Dupuis (1970) is adopted for genital structures.

Comments. Differential characters used by Distant (1889) to create the genus Architas are relatively minor, and, vary between species. Most of the characters conform to the requirements of the genus Cataulax, specially the genitalia of both sexes. The genera related to Cataulax have already been studied by the authors: Sympiezorhincus Spinola, 1837 was revised by Becker & Ruckes (1969), Ablaptus Stål, 1864 by Becker & Grazia (1989), Agaclitus Stål, 1864 by Becker & Grazia (1992) and Uncinala Ruckes, 1965 by Becker & Grazia (1995). The relationships among these genera can be found in these papers, and are extensively discussed in Becker & Grazia (1989, 1992). This is the first time that Cataulax is brought into the vicinity of these genera.

Relatively large species; three to five pale, laevigate, longitudinal lines on head, intercalated with four subparallel rows of fine piceous punctures; eight small clusters of piceous punctures on pronotum, two at each humerus and four across crest of the disc, and three, more or less parallel longitudinal lines of fine punctures on exocorium, endocorium with patches of punctures (Fig. 1).

Comments. This species is the largest one and as C. froeschneri and C. subtiliterconspersus has lobed and spined parameres. It can be distinguished from them by the pattern of the membrane venation; in the last two species three or four external veins are convergent to a darker peg.

Etymology. This species is dedicated to Dr. Richard C. Froeschner for his contribution to the knowledge of the Heteroptera.

Comments. By the structure of the parameres and the pattern of the membrane venation this species is similar to C. subtiliterconspersus; the presence of bands of fuscous punctures on head and pronotum and arranged in four darkest patches along basal portion of scutellum distinguish C. froeschneri from C. subtiliterconspersus in which the punctures do not form bands or patches.

Distinctly shorter, and less densely punctured than in C. eximius, but sometimes punctuation is arranged in longitudinal lines or in patches as in that species. Apex of scutellum subtriangular. Corium hardly longer than scutellum. Rostrum clearly surpassing the middle of the fourth abdominal sternite. Posterior margin of metasternum almost as wide as anterior margin; median mesosternal plate conspicuously convex anteriorly.

Comments. Similar to C. radians by having simple parameres and membrane with subparalell veins ending well before apical margin. In C. pudens the apical margin of hemelytral membrane is slightly truncate and feebly sinuate but in C. radians it is straight.